Its clear that someday the people will stop using cash money and will pay everything on electronic devices. The question is just when? When you look today, there are a lot of people who pay everyday with credit card and other electronic payment method. And it comes everyday more. So the cash fiat money will someday dissappear. But if it will be replaced by cryptocurrencies, that is the big question!
I guess humanity won't give up using money soon cause there're many undeveloped regions. What concerns developed countries, they're quickly shifting to electronic money! That's good for the economy and environment!